"Hallux Valgus, Bunion and Associated Deformities of the First Metatarsal-Phalangeal-Sesmoid Joint Apparatus" ...A Synopsis

1. Hallux Valgus, Bunion and Primus Varus

A. Definitions

  1. Bunion is the soft tissue swelling over the medial aspect of the first MTP.
    Frequently with associated bursitis, this bump is often irritated by shoe pressure.
  2. Hallux valgus is a lateral deviation of the great toe. This deviation often involves rotation in the frontal plane, and adaptation of the articulating cartilage to a valgus position. This deformity may be aggravated and exagerated by a hallux interphalangeus, a lateral deviation within the phalanx or interphalangeal joint itself.
  3. Primus Varus is a triplane deformity involving dorstflexion, medial deviation and varus rotation of the head of the first metatarsal. This deformity is very significant and often involves instability or hypermobility of the metatarsalcuneiform joint.
  4. Sesmoid Position. The tibial and fibular sesmoids are invested in short flexor tendon, and have articulating cartilage on their dorsal surface. They articulate with the plantar aspect of the first metatarsal head, and glide in two grooves separated by a crista. With valgus deviation of the hallux, and varus of the first metatarsal, these sesmoids "drift" into the first intermetatarsal space, with a resultant contracture of the lateral soft tissues, and mechanical erosion of the articulating surfaces. Once the crista is flattened, the joint loses most of its transverse and frontal plane stability.


B. Signs and Symptoms

  1. Pain, in and/or out of shoes over and around bump and joint.
  2. Associated bursitis over prominence.
  3. Painful motion and loss of motion.
  4. Difficulty fitting shoes.
  5. Transfer pain to the 2nd and 3rd MTP's due to medial instability.
  6. Callous medial hallux and sub 2nd.
  7. Crowding of lesser digits and hammertoes.
  8. Neuroma  (Joplin or Morton type).
  9. Nonspecific complaints related to spasm, favoring and altered gait pattern due to pain.


C. Etiology

  1. Genetics (familial predisposition).
    a.  Ligamentous laxity, hypermobility.
    b.  Long first metatarsal.
    c.  Hyperpronated foot, for whatever reason:
         1.  Metatarsus varus or adductus.
         2.  Rearfoot varus.
         3.  Equinus.
         4.  Coalition (Peroneal Spastic Flatfoot).
         5.  Tibial torsion deformities.
         6.  Traumatic (ie Posterior tibial tendon dysfunction, calcaneal fracture, lisfranc injury, etc.).
  2. Traumatic.
  3. Iatrogenic.
    a.  Sesmoidectomy.
    b.  Surgical failures.
  4. Systemic disease.
    a.  Arthritis (rheumatoid).
    b.  Steroid induced.


D. Treatment

  1. Conservative measures focus primarily on accommodating the deformity to reduce pressure, and will not cause reversal of the deformity.
    a.  Shoe modification.
    b.  Bunion Shield.
    c.  Functional orthosis. These devices may significantly reduce progression of deformity by reducing pronation and thereby stabilizing the first ray. This promotes normal functioning of the windlass mechanism, reduces jamming at the MTP joint. Problem is with device in shoe, shoe fits tighter and bump gets irritated. Many patients (especially ladies) are reluctant to wear larger shoes.
  2. Surgical Correction. There are hundreds of ways to address this syndrome of hallux valgus, bunion and primus varus. Historically (See Fig. 1) there are many approaches and modifications, a sign of the need for continued improvement of technique. The most important principles of performing an adequate reduction are: (See Fig. 2).
    a.  Reduce primus varus in all three planes.
    b.  Reduce Proximal Articular Set Angle (PASA).
    c.  Re-align hallux on metatarsal.
    d.  Restore sesmoid position.
    e.  ADDRESS PRIMARY DEFORMITY, IF ONE EXISTS! (met adductus, etc.).



2. Hallux Limitus, Rigidus, Primus Elevatus and Degenerative Disease

A. Definitions

  1. Hallux limitus and rigidus refer to loss or absence of motion at the first metatarsal-phalangeal sesmoid apparatus.
  2. Primus elevatus describes an elevated or dorsiflexed structural or functional position of the first metatarsal in relation to the lesser metatarsals. (See Fig. 3).


B. Signs and Symptoms

  1. Pain.
  2. Loss of Motion.
  3. Dorsal bump and bursitis.
  4. Difficulty fitting shoes.
  5. Transfer pain to lesser metatarsals.
  6. Nonspecific and postural complaints due to altered gait pattern.


C. Etiology

  1. Traumatic.
    a.  Gross trauma, leading to ligamentous or tendon (peroneus longus) avulsion, osteochondral fracture, metatarsal fracture, etc.
    b.  Repeated microtrauma from primus elevatus*, jamming and secondary adaptive changes. *(this causes disruption of the windlass mechanism of Hicks, and leads to jamming of the phalanx on the metatarsal head as well as sesmoid jamming plantarly).
    c.  Iatrogenic (usually post bunionectomy or osteotomy).
  2. Congenital (related to).
    a.  Talipes equinovarus.
    b.  Congenital pes planus and calcaneovalgus.
    c.  Collapsing pes plano-valgus.
    d.  Congenital primus elevatus.


D. Treatment

  1. Conservative measures focus primarily on accommodation, and taking stress away from the first MTP.
    a.  Shoe modification.
    b.  Functional orthosis to support 2-5 and allow first ray to float down, or with extension to limit motion at joint.
  2. Surgical Correction.
    a.  Cheilectomy.
    b.  Osteotomy to reduce elevatus or proximal set angle.
    c.  Fusion.
    d.  Arthroplasty with or without implant.
    e.  Autogenous implant with or without osteotomy.
    f.  Investigational procedures for joint salvage (Intra-articular wedge resection osteotomy, for example).

 

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